1.work 2. skin 3. sand 4. rain 5. postcard 6. traffic 7. accident 8. air 9. cloud 10. information 11. happiness 12. news 13 furniture 14. entertainment

Please help to check the above whether they are all correct, thanks & regards.

3 answers

These are countable: postcard, accident, cloud. These can be countable: work, skin.
I think Ms. Sue means, "These can not be counted: work, skin."

count nouns (can be counted, one by one)
postcard
accident
cloud

All the rest are non-count nouns (not countable, one by one).
The taxidermist showed us five different skins from animals he killed.

The museum displayed 20 works of 17th- century painters.